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Author Topic: wishbone 3 link questions  (Read 3020 times)

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wishbone 3 link questions
« on: October 04, 2009, 08:18:19 PM »
ok i am going a different direction with the truck than i had discussed on here. i was going to go for more of a handling truck, but decided that really isnt me. i like to go fast, but just in a straight line. outside of that, just cruise around.

i decided to bag the luv truck. already started on the new frame(pics in projects section) i think a wishbone 3 link is what i want to do.

i will be running 30" long lower bars. the main thing im worried about with my intended uses is wheel hop. with the ride height i want, and the way i want it setup, im kind of limited.

heres a sideview drawing. i just got a new comp, loaded the new calculators getting excited cause it has excel, but wont open all the files cause it says they are to long or some shit.. but anyways, hopefully someone can help let me know if i will have wheel hop with this setup. the bars look like they will intersect wayyyyy in front of the truck..

trucks ride height will be 2" off ground..


Re: wishbone 3 link questions

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Re: wishbone 3 link questions
« Reply #1 on: October 04, 2009, 09:29:19 PM »
gah.. i did some changing up.. i had the cog line going from rear tire to tranny area for some reason.. i changed it to camshaft area..  looks like i can get both bars to cross pretty close to center of cog line.. ill redraw it up tomorrow and make more sense of it all.. hopefully i can get some help and get this planned out so i can order my wishbone.

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Re: wishbone 3 link questions
« Reply #2 on: October 05, 2009, 08:02:14 AM »
I honestly don't know much about wishbone 3 links.
Wheel hop typically comes from the front arms being pointed down. Try to get the lower bars level at ride height.

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Re: wishbone 3 link questions
« Reply #3 on: October 05, 2009, 04:17:00 PM »
Wheel hop and brake hop can also be cause by too short of an instant center. I've read you want the IC over 60" from the axle centerline w/ most cars..... I think it might need to be little longer w/ trucks since the front to rear weight ratio is a little more than standard vehicles.
I've also read you can get brake hop from too high of an Anti-Squat percentage which will effect weight transfer to the front, causing the rear tires to lift when the back end comes up. This is called "Anti-Lift" and is the counterpart to Anti-Squat. If you want hight Anti-Squat, you will get high Anti-Lift.
Soft durometer bar end bushings can also be a cause of wheel hop.
« Last Edit: October 05, 2009, 04:35:44 PM by journeyman »
Chris
1991 S-10 std. cab~Sm block 350 ~ 5-speed
Satchell-Link rear suspension ~ Ford 8" rear end......and all sorts of other shit too.

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Re: wishbone 3 link questions
« Reply #4 on: October 05, 2009, 04:35:13 PM »
ok. hmm. so lower bars level at ride height, and uppers pointed down some...  so then that kind of does away with me wanting to make both bars intersect on my cog line.. if they did my wishbone would be pointed like straight down lol..

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Re: wishbone 3 link questions
« Reply #5 on: October 05, 2009, 04:39:15 PM »
Correct. You are dialing in roll UNDERSTEER with your LCAs parallel to the ground. When trying to get understeer, you will normally lose Anti-Squat with this type of suspension.
Chris
1991 S-10 std. cab~Sm block 350 ~ 5-speed
Satchell-Link rear suspension ~ Ford 8" rear end......and all sorts of other shit too.

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Re: wishbone 3 link questions
« Reply #6 on: October 05, 2009, 04:44:26 PM »
i guess im gonna make the wishbone bracketry have several holes so i can adjust it and play around with it some once i find a general area it should be at.

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Re: wishbone 3 link questions
« Reply #7 on: October 05, 2009, 04:50:26 PM »
Usually 4-links have the lower bars pointed up for a high Anti-Squat. When doing this, you are dialing in roll OVERSTEER... which is why most drag cars are only good in a straight line (geometry-wise). So if thats what you are into, go ahead and start angling your LCAs upward, just don't be throttling into curves on the street unless you want your ass-end swinging around.
Chris
1991 S-10 std. cab~Sm block 350 ~ 5-speed
Satchell-Link rear suspension ~ Ford 8" rear end......and all sorts of other shit too.

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Re: wishbone 3 link questions
« Reply #8 on: October 05, 2009, 05:02:53 PM »
im gonna draw something up, get some numbers and see where im at from there. i havent found a calculator for a wishbone 3 link.. can i just use a 4 link calculator?

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Re: wishbone 3 link questions
« Reply #9 on: October 05, 2009, 05:13:44 PM »
I'd say the 4-link calc is the one to use for this, only cuz you won't be using a panhard bar (right?). Only thing you won't be able to determine is the roll center in plan view if it's an offset wishbone

here's a  calc. link
http://mysite.verizon.net/triaged/4linkcalcv15html/index.html

bottom right hand corner is the link for the Excel download
« Last Edit: October 05, 2009, 05:15:18 PM by journeyman »
Chris
1991 S-10 std. cab~Sm block 350 ~ 5-speed
Satchell-Link rear suspension ~ Ford 8" rear end......and all sorts of other shit too.

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Re: wishbone 3 link questions
« Reply #10 on: October 05, 2009, 05:29:02 PM »
ok cool thanks, i just downloaded it..

heres what i came up with.. kinda hard to see..

frame is setup 2" off the ground
center of axle to center of lower bar is 7.5" and bar runs parallel to ground
center of axle to center of upper bar is 5.5" and points down about 6 degrees
axle center line out it 70" it intersects the cog line.



 

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